Britbike forum Forums British Motorcycle specific Brands Triumph bulletin board Crankshaft Stud: Blue Loctite or no?

Hi All -

Getting ready to reinstall my alternator. When I removed the rotor, the stud came out with the nut. Last time I was in here back in 2011, I used a bit of blue loctite on the nut, so I expect that's why the stud came out. I'm going to double-nut the stud and remove the rotor nut but what do I do with the stud:

a) Screw it back in to the crank-end finger tight and torque nut per spec?

b) Use blue Loctite on the nut AND the stud?

c) Double nut the stud and torque it into the crank?

d) Some combination of above?

Cheers,

Steve

My understanding of studs are that they should just be snugged not tightened or torqued. It's the interference of the threads and the stretch of the stud that does the holding once the nut is torqued to the proper spec. A bit of blue loctite on the stud might keep it from backing out first instead of the nut coming off. But not sure why it would be a concern if it did. If you ever need to remove the
stud you should be able to break the bond on the blue with double nutting the stud.

I Loctite the sprocket splines, the rotor, the stud and the nut.

It's one of my favourite Loctite areas!

You need to change you sig to "Professional Loctite enthusiast".

As an American, I have difficulty discerning between Scottish humor and seriousness...especially with so many tongue-in-cheek posts regarding Loctite!

Steve

I wouldn't joke about mechanical queries.

Thank you triton!

(you, too, htown)

Cheers,

Steve

No, really! Can we take you seriously?

WWJD?

(what would John do?)

I am with Triton, except I wouldn't Loctite the splines. (BLUE) or wear a kilt - I would scare too many little children...

Be sure to wash all of the oil from stud and be sure you clean inside the crank and nut. I prefer denatured alcohol, as it is a good solvent for oil based products and isn't as harmful as some of the brake cleaners.

I (probably) wouldn't Loctite perfect splines either, but I've found that slightly worn ones are useable, with Loctite.

I usually loctite the stud in, but doesn't the nut have a lockwasher?

Thanks John, et al -

I had planned on wrapping the crank and sprocket with a shop rag and spraying the threads in the crank with brake cleaner. That stuff IS pretty nasty, I'll give the denatured alcohol a go.

tiger cub - yes it has a tab washer that can be bent and locked against the flat of the nut, but using the blue loctite makes that step unnecessary.

Cheers,

Steve

I reckon those tab washers are worse than useless. Loctite works better, with no tab washer.

I also put a small amount of blue Loctite between the rotor and the crank.I don't get too serious, but at least wipe the oil off first. You'll get it off with a puller, without much trouble, next time. It's better than having it come loose and rattle around.

Thanks Pete -

Ironically enough I was just reading a post of yours that said you can use engine mount nut(s) to double nut the stud (7/16"-20 UNF #14-0304).

Didn't feel like futzing with that, so I looked up all the 7/16"-20 UNF nuts on stainlessbits.com and cross-referenced them with my parts book.

Found one on the brake torque stay (rear disc #14-1304) and the locknuts used on the directional stems (#14-0404).

Lucky for me, I had some spare directional stems with locknuts in my parts cabinet.....job done! :bigt


Cheers,

Steve